Hi Chris
It is a small world - I was just prowling the 78TA site for pictures and saw the post for your 78TA and thought - that engine bay looks just like the TA I saw Saturday night! Then as read the post I figured out it was you that I was talking to on Saturday.
The car looks great both in the photos and in person.
The check you build sheet for the Y88 code - As recall the sheet showed paint code of 50. Check some of the other sites for information on the Y88 cars -
http://www.firebirdtransamparts.com/bandit/bandithistory2.htm. I dont recall the production date that was on the build sheet you have. Also you said you have the orginal bill of sake for the car - check that for the SE option. There are a lot of clues that make me thing yours is a Y88 car.
After all is said and done it is your car,if you like a black TA then leave it black.
If it will add something special to the car for you by having it Solar Gold and knowing that you have a very rare TA then it may be time to repaint.
The car is your car to enjoy as you like it.